CA1193853A - Reinforced blade end for a retractable tape measure - Google Patents
Reinforced blade end for a retractable tape measureInfo
- Publication number
- CA1193853A CA1193853A CA000417225A CA417225A CA1193853A CA 1193853 A CA1193853 A CA 1193853A CA 000417225 A CA000417225 A CA 000417225A CA 417225 A CA417225 A CA 417225A CA 1193853 A CA1193853 A CA 1193853A
- Authority
- CA
- Canada
- Prior art keywords
- blade
- blade member
- tape measure
- reinforcement member
- retractable tape
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Tape Measures (AREA)
Abstract
REINFORCED BLADE END FOR A
RETRACTABLE TAPE MEASURE
Abstract Of The Disclosure An improved reinforced blade end for a retract-able tape measure is disclosed. A reinforcement member varying in width along its length is provided at the free end of the blade and secured thereto with its vertex disposed away from the blade end so as to avoid breaking and tearing of the hook or finger tab attachment.
RETRACTABLE TAPE MEASURE
Abstract Of The Disclosure An improved reinforced blade end for a retract-able tape measure is disclosed. A reinforcement member varying in width along its length is provided at the free end of the blade and secured thereto with its vertex disposed away from the blade end so as to avoid breaking and tearing of the hook or finger tab attachment.
Description
~31~3 REINFORCED BLADE END FOR A
RETRACTABLE TAPE MEASURE
BACKGROUND OF THE INVENTION
1. Field Of The Invention This invention is in the field of retractable measuring tapes. More particularly, -the invention relates to blade end attachments to provide increased strength at the blade end of such -tapes in order to overcome the breaking and tearing action that commonly occurs at the junction of the blade and the metal hook or finger tab attachment which contacts the workpiece.
RETRACTABLE TAPE MEASURE
BACKGROUND OF THE INVENTION
1. Field Of The Invention This invention is in the field of retractable measuring tapes. More particularly, -the invention relates to blade end attachments to provide increased strength at the blade end of such -tapes in order to overcome the breaking and tearing action that commonly occurs at the junction of the blade and the metal hook or finger tab attachment which contacts the workpiece.
2. Prior Art Blade end failures frequently occur as a result of the twisting, breaking and tearing of the metal hook or ring attachment from the blade end when the attachment is caught in the workpiece. Blade end failures may also result from excessive whipping of the blade end attachment against the tape housing as the blade is retracted into the housing, particularly if blade retraction is assisted by a spring re-turn.
Devices, such as those of McCully U.S. patent 2,5~4,272, Quenot U.S. patent 3,473,235 and Wall U.K.
patent 15,416, generally provide metal plates which increase the thickness and strength at the blade end. However, in reality, such devices merely move the line of breakage from the extremity of the tape to the junction where -the reinforcement plates are attached to the tape. While these supporting metal plates are riveted to the tape, ~' 31~5:3 they have also been fastened in a slidable arrangement as in Witchger U.S. patent 2,005,850. The common supported metal blade results in a rigid blade end structure adjoin-ing a relatively weak and ragile unsupported blade. This junction of the blade end structure and the blade becomes a line of high stress since the blade will tend to bend about a line at that junction when the blade end attachment is caught in the workpiece. ~epeated or s~vere bending, of course, results in fracture of the blade at this line.
Keuffel U.S. patent 2,105,149 represents a different approach. The tape, in that instance, is dis-posed between resilient steel strips which curve toward the tape so as to engage the tape only by the end edges of the strips. However, that design, while providing increased strength at the blade end, still suffers the defect of having its fracture and bending lines coincide.
Moreover, the Keuffel structure is relatively expensive and cumbersome.
Keuffel U.S. patent 297,417 and Soltman U.S.
patent 400,961 provide a strap, made of leather or linen in Keuffel and of metal in Soltman, which strap connects the finger tab holder to the measuring tape. The strap's two arms are secured to the u~per and lower surfaces of the tape. In either case, the strengthening piece under-goes dual stresses, i.e., the stress of a connecting piece for the finger tab attachment and the tape and the stress of reinforcing the blade end. While the me-tallic strength-ening piece of Soltman offers reinforcement at the blade end superior to that available from the leather or linen lapping of Keuffel, the Soltman design allows the reinorce ment piece to be caught in the workpiece in the same way that the hook or ring finger tab attachment can be caught.
Thus, none of the prior art devices are fully effective in solving the problem of blade end failures.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved reinforced blade end is provided wherein a specially designed reinforcement member is secured to the blade of a flexible metallic measuring tape in such a way that it will resist the tearing and breaking action which occurs when the hook or ring finger tab attachment is caught and twisted in a workpiece. The present invention also effectively resists flexing and tape blade damage caused by the whipping action of the tape as it is rewound into the tape housing whereby the hook or ring attachment may strike violently against -the tape housing during a spring-return rewinding of the tape. The reinforcement member of the preferred embodiment does not serve as a connecting member for the tape hook attachment and the blade end. The junction of that part of the blade that is supported by the reinforcement member and the part that is unsupported defines a line of high stress and, consPquently, i.s a line of severe weakness on the blade. Thus, -this invention avoids a sudden loss in reinforcing support at the blade end and also avoids the coincidence, in existing devices, of the bending line of the blade end with the line of weakness described above. The normal bending line is a transverse axis of the blade about which the blade flexes.
Accordingly, in a preferred embodiment of this invention, the retractable tape measure comprises a trans~
versely curved blade member having concave-convex surfaces,
Devices, such as those of McCully U.S. patent 2,5~4,272, Quenot U.S. patent 3,473,235 and Wall U.K.
patent 15,416, generally provide metal plates which increase the thickness and strength at the blade end. However, in reality, such devices merely move the line of breakage from the extremity of the tape to the junction where -the reinforcement plates are attached to the tape. While these supporting metal plates are riveted to the tape, ~' 31~5:3 they have also been fastened in a slidable arrangement as in Witchger U.S. patent 2,005,850. The common supported metal blade results in a rigid blade end structure adjoin-ing a relatively weak and ragile unsupported blade. This junction of the blade end structure and the blade becomes a line of high stress since the blade will tend to bend about a line at that junction when the blade end attachment is caught in the workpiece. ~epeated or s~vere bending, of course, results in fracture of the blade at this line.
Keuffel U.S. patent 2,105,149 represents a different approach. The tape, in that instance, is dis-posed between resilient steel strips which curve toward the tape so as to engage the tape only by the end edges of the strips. However, that design, while providing increased strength at the blade end, still suffers the defect of having its fracture and bending lines coincide.
Moreover, the Keuffel structure is relatively expensive and cumbersome.
Keuffel U.S. patent 297,417 and Soltman U.S.
patent 400,961 provide a strap, made of leather or linen in Keuffel and of metal in Soltman, which strap connects the finger tab holder to the measuring tape. The strap's two arms are secured to the u~per and lower surfaces of the tape. In either case, the strengthening piece under-goes dual stresses, i.e., the stress of a connecting piece for the finger tab attachment and the tape and the stress of reinforcing the blade end. While the me-tallic strength-ening piece of Soltman offers reinforcement at the blade end superior to that available from the leather or linen lapping of Keuffel, the Soltman design allows the reinorce ment piece to be caught in the workpiece in the same way that the hook or ring finger tab attachment can be caught.
Thus, none of the prior art devices are fully effective in solving the problem of blade end failures.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved reinforced blade end is provided wherein a specially designed reinforcement member is secured to the blade of a flexible metallic measuring tape in such a way that it will resist the tearing and breaking action which occurs when the hook or ring finger tab attachment is caught and twisted in a workpiece. The present invention also effectively resists flexing and tape blade damage caused by the whipping action of the tape as it is rewound into the tape housing whereby the hook or ring attachment may strike violently against -the tape housing during a spring-return rewinding of the tape. The reinforcement member of the preferred embodiment does not serve as a connecting member for the tape hook attachment and the blade end. The junction of that part of the blade that is supported by the reinforcement member and the part that is unsupported defines a line of high stress and, consPquently, i.s a line of severe weakness on the blade. Thus, -this invention avoids a sudden loss in reinforcing support at the blade end and also avoids the coincidence, in existing devices, of the bending line of the blade end with the line of weakness described above. The normal bending line is a transverse axis of the blade about which the blade flexes.
Accordingly, in a preferred embodiment of this invention, the retractable tape measure comprises a trans~
versely curved blade member having concave-convex surfaces,
3~
a metal hook finyer tab attachment and a reinforcement member having a decreasing width in a direction opposite the blade end. The reinforcement member is preferably secured to the blade member by an eyelet adjacent a ver-tex of the reinforcement member. The other end of the reinforce-ment member is secured to the blade member by two rivets and, preferably, has a width smaller than that of said blade member. The reinforcement member is of substantially the same transverse radius of curvature as the blade member and lies adjacent -to and in close uniform contact with the curved surface of the blade member. It is preferably so located that the longitudinal center lines of the blade membex and reinforcement member are substantially coincident.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to describe the present invention more fully the following drawings are provided in which:
Fig. 1 is a perspective view of a retractable tape measure in its housing shown with the blade member and adjoining metal hook finger tab attachment in partially extended position;
Fig. 2 is an enlarged bottom view of the blade member with metal hook attached taken along the line 2-2 of Fig. 1 and showing a preferred form of the reinforcement member;
Fig. 3 is a side elevational view of the blade member with the reinforcement member and metal hook finger tab attachment shown in solid lines in the normal position and the hook member shown in broken lines in a distorted posltlon;
Fig. 4 is an enlarged sectional view of the blade member taken along the line 4-4 of Fig. 3;
31~Si3 Fig. 5 is a further enlarged sectional view of ~he blade member with reinforcement member and metal hook finger tab attachment taken along the line 5~5 of Fig. 2;
Fig. 6 is a bottom view of yet another embodiment showing the reinforcement member secured to the blade member by spot welds;
Fi~. 7 is an enlarged side elevational vi~w of the embodiment of Fig. 6 taken along the line 7-7 of Fig. 6;
Fig. 8 is a bottom view of still another embodi~
ment showing a gently tapering fibreglass tab reinforcement memher adhered to the bottom of the blade;
Fig. 9 is an enlarged side elevational view of the embodiment of Fig. 8 taken along the line 9-9 of Fig. 8;
Fig. 10 is a top view of an embodiment showing a clear plastic reinforcement member adh~red to the face of the blade;
Fig. 11 is an enlarged side elevational view of the embodiment of Fig. 10 taken along the line 11-11 of Fig. 10;
Fig. 12 is a bottom view of an embodiment showing a reinforcement member in the form of a narrow strip disposed some distance away from the blade end extremity;
Fig. 13 is an enlarged side elevational view of the embodiment of Fig. 12 taken along the line 13-13 of Fig. 12;
Fig. 14 is a bottom view of an embodiment showing a reinforcement member in the form of wire mesh or poly~mesh;
Fig. 15 is an enlarged side elevational view of the embodiment of Fig. 14 taken along the lines of 15-15;
3~S3 Fig. 16 is a bottom view of an epo~y p~wder-coated blade member and reinforcement member secured by epoxy adhesive ~o ~he blade memher; ~d Fig. 17 is a side elevational view of the embodi-ment of Fig. 16 taken along the line 17-17 of Fig. 16.
DETAIhED DESCRIPTION OF
TEIE lNv~ ION
~ eferring to Fig. 1, reinforced blade member 12 of the retractable tape measure of this embodiment is ~hown with blade member 12 exposed in sli~htly extPn~e~
position from tape housing 10. slade melDber 12 has metal hook finger tab attachmerlt 14 held by ~wo ri~vets 16 on its c:onc:ave uppex surface 28. Fi~ger tab attachment 14 c:om-prises abutting end 18 and supportin~ end 32.
The supporting end 32 has tapered edges 33. Abutting end 18 normally abuts 'che workpiece when the tape measure is in use and is slidably movable along the longitudinal axis of blade member 12. Abut~ing end 18 is perpendicular to supportiIlg erld 32 which engages ~he blade m~mber 12.
Blade me~b~r 12 is rewound throug~ aperture 34 of tape housing 10 when the tape is not in use.
In Fig. 2 reinforcement member 20 of this pre-ferred embodiment has a varying width which decreases to a narrow end or vertex 22 remote from adjoi~ing free end 26 of blade member 12 and is held by eyelet 24 (or a rivet~
to blade member 12. The other end 36 of reinforcement member 20 is secur~d to convex lower surface 38 of blade member 1~ by two rivets 16 which also secure the supporting end 32 (in dotted lines) of finger tab attachme~t 14 to concave upper surface 28 (Fig. 1). Abutting end 18 of finger tab attac~ment 14 is shown in e~tended position from adjoining free end 26 of blade member 12. Finger ~ab ~3~ii;11 attachment 14 is slidable between the extended position shown in Fig. 2 and a retracted position (not shown) so as to accomnodate both inside and outside measurements.
Reinforcement member 20 is shown with other end 36 of a width smaller than that of adjoining free end 26 of blade member 12 and is located on blade member 12 so that the longitudinal center lines of said blade member 12 and said reinforcement member 20 are substantially concident.
Vertex 22 of of reinforcement member 20 and securing rivets 16 preferably all lie on the longitudinal axis of tape blade member 12.
In Fig. 3 abutting end 18 is shown in solid lines in normal position perpendicular to the longitudinal axis of blade member 12 and in broken lines in dis-torted position such as occurs when the tape measure has been subjected to abuse, e.g., when the finger tab attachment 14 has been caught in the workpiece. Under conditions of such abuse reinforcement member 20 remains relatively in-tact, secured to blade member 12 at its vertex 22 by eyelet 24 (or a rivet) and at other end 36 by rivets 16.
Reinforcement member 20 tapers to vertex 22. As shown in Fig. 3, there is vir-tually no overlap between eyelet 24 and vertex 22 of blade member 12. Because there is negligible overlap at this extremity, the possibility of vertex 22 being caught in the workpiece is i ni i zed.
Tapered edges 44 allow the distribution of the reinforce-ment effect of the reinforcement member 20 to change gradually from a maximum in the region of the rivets 16 of blade member 12 to a minimum at vertex 22, thereby avoiding a sudden loss in reinforcing support. Because -the junction of the supported ancl unsupported parts of blade member 12 ~33~3S:3 define a line of high stress and, therefore, of severe weakness, reinforcement member 20 also avoids a coincidence of the bending line of blade member 12 (as the blade is fle~ed) with that line of weakness.
In Fig. 4 blade member 12 is shown secured between supporting end 32 of finger tab attachment 14 on concave upper surface 28 and reinforcement member 20 on convex lower surface 38. Abutting end 18 is shown perpen-dicular to the longitudinal axes of blade member 12. The location of reinforcement member 20 on convex lower sur-face 38 tends to r~X~rl 7e the reinforcement effect of reinforcement member 20 on blade member 12.
In Fig. 5 eyelet 24 and rivets 16 are shown disposed on a longitudinal axis of blade member 12.
Eyelet 24 supports reinforcement member 20 at vertex 22 thereby providing negligible overlapping of supporting member 20 at eyelet 24. Finger tab attachment 14 is shown with abutting end 18 in e~tended position for outside measuring use of the tape. The gap 48 between abutting end 18 and adjoining free end 26 of blade member 12 corre-sponds to gap 50 in each of longitudinal slots 46 in supporting end 32. Rivets 16 project through longitudinal slots 46 thereby allowing supporting end 32 of finger tab attachment 14 to be longitudinally slidable. During outside measurement inner surface 52 of abutting end 18 abuts the workpiece and abutting end 18 is extended as shown. For inside measurement outer surface 54 abuts the workpiece thereby causing gaps 48 and 50 to close.
Several alternative embodiments of the instant invention are shown in subsequent drawings. The reinforcing effect, of course, will vary for each embodiment shown.
33~3 In Figs. 6-17, parts which are common to the parts shown in Figs. 1-5 are identified by the same nur~er.
In Figs. 6 and 7 reinforcement member 20 is secured to blade member 12 by spot welds 30 adjacen-t the vertex 22 and longitudinal side edges 42. This embodiment offers an alternate form of securing reinforcement member 20 to blade member 12 and, as shown in Fig. 6, increases the number of poin-ts at which supporting member 20 is secured to blade member 12.
In Figs. 8 and 9 a gently tapering fibreglass tab 58 is shown in place of reinforcement member 20 of Fig. 6 and 7. Fibreglass tab 58 is adhered to convex lower surface 38 of blade member 12. Thus, the embodiment of Fig. 8 offers maximum securement of the fibreglass tab 58 strengthening piece to blade member 12.
In Figs. 10 and 11 a clear plastic reinforcement member 60 is shown adhered to concave upper surface 23 of blade member 12 secured thereto by rivets 16 which also secure supporting end 32 of finger tab attachment 14. If desired, at least the vertex end 61 o~ the clear plastic reinforcement member 60 may be adhesively secured to the face (concave upper surface 28) of blade member 12 to facilitate -the rewinding o~ blade member 12 into tape housing 10. Since plastic reinforcement member 60 is transparent, reading of measuring scale 70 on concave upper surface 28 is uni ~:cded.
In Figs. 12 and 13 reinforcement strip member 62 is shown with a cross sectional width substantially smaller than that of the embodiment illustrated in Figs~ 10 and 11.
Reinforcement strip member 62 has substantially semicircular ends 64 which, like the other embodiments discussed above, ~3~
are tapered and thereby avoid having the bending and high stress lines coincide. Reinforcement strip member 62 is shown secured to convex lower surface 38 by an eyelet 24 (or rivet3 at one end and by a rivet 16 at the other end, which rivet also s~cures supporting end 32 of finger tab attachment 14. In the embodiment of Fig. 12 reinforcement strip member 62 is displaced from adjoining free end 26.
In Figs. 14 and 15 an alternative embodiment showing a wire mesh (or polymesh) reinforcement member 66 is the strengthening piece and is secured to convex lower surface 38 of blade member 12 by an appropriate adhesive coating.
In Figs. 16 and 17 an epoxy powder coated rein-forcemènt member 68 is secured to convex lower surface 38 of epoxy powder coated blade member 12 by an epoxy adhesive coating.
Tests were conducted to obtain physical data comparing ~he standard blade with the reinforced blade of this invention. The results, set forth in Table 1 below, show a substantial increase in strength with the reinforced blade -- especially in the high stress angles of pull at 90 degrees upward and 90 degrees downward with reference -to the position of the finger tab.
Six groups of blades were tested, consisting of 1/2", 3/4" and 1" width blades of both standard and rein-forced design. Each blade was clamped in a holding fixture into which a dynamometer was hooked. The finger tab was then clamped in a vise and the whole assembly was pulled manually from varying angles relative -to the vise. An approximate force limitation was observed as a cut-off for safety (1/2" wide reinforced blades showed failures between ~3~3 90 lbs. and 110 lbs. at 90 degrees up and 90 degrees down~. Data wa~ recorded after each pull.
The compiled data in Table 1 (below) indicate a substantial gain in strength by the reinforced blade when compared with the standard design. While the ultimate s-trength of the reinforced blade was not fully determined, the cut-off limit was used as a benchmark with which the standard blade was compared. ThereEore, it should ~e noted that other -testing methods might yield higher gains in strength for the reinforced design.
However, the data indicates the gain for the 1/2" wide reinforced design to be at least 5.1 times greater than the standard blade in the 90 degree upward pull while gaining at least a si~ fold increase in the 90 degree downward pull. Lesser gains in strength show up for the smaller angles of pull for two reasons: the first, that less bending stress is exerted on the blades from finger tabs and rivets; and the second, that the standard blade data is compared with the pull limitation data where breakage did not occur.
The 3/4" wide reinforced blades ~howed larger gains in strength than the 1/2" wide blades. In the 90 degree upward pull, the reinforced design showed at least an eight fold advantage, while the 90 degree downward pull revealed at least a 13.8 times increase over the standard design. The smaller angles showed only one failure for the standard blades (45 degree upward pull at 70 lbs.).
The 1" wide reinforced blade showed similar resul-ts in the test. A strength increase of at least 9.3 times was achieved over the standard results in the 90 degree upward pull. The 90 degree pull showed a 6.5 times advantage by the reinforced design. However, the tests performed with the lesser angles of both -the standard design and the reinforced design resulted in no failures.
Table 1 ABUSE TEST RESULTS DATA SUMMARY
Avera~e Force (Lbs.) Req'd. For Blade Failure Pull 1/2" Wide 1/2" Wide Angle Standard Blades Reinforced Blade 90 Up 21.5 lQg.2 33% failed 90 Down 18.8 112 (no failures) 60 Up 41.9 128.3 "
60 Down 55.0 101.3 50~ failed 45 Up 76.9 62h failed 101. 6 (no failures~
45 Down 93.3 (no failures) 120 "
0 ~No Breakage) 101.6 (Avg.) for 137.5 ~Avg.) or three blades two blades Pull 3/4/" Wide 3/4/" Wide Angle Standard Blade Reinforced Blade 90 Up 12.6 110(no failures) 90 Down 8.2 112.9 "
60 Up 100 (no failures) 110~ "
60 Down No Data 110 I' 45 Up 116.3 (no failures) 120 one failure at 70 45 Down 100 ~no failures) 110 0 (No Breakage) 105.0 (Avg.) for 120.0 two blades Pull 1" Wide 1" Wide Standard Blade Reinforced Blade 9oo Up 10.7 111.3 (no failures) 90 Down 18.3 119.0 60 Up 110.0 (no failures) 107.5 "
60 Down 110.0 " 120/0 "
45 Up No Data 112.5 "
45 Down 110.0 (no failures) 115.0 "
0 (No Breakage) 115.0 110.0 (Avg.) for two blades ~3~
As is illustrated by the drawings and the Abuse Test Results Data Summary of Table l, the improved reinforced blade end for the retractable tape measure of this invention provides increased stren~th and durability at the blade end thereby preventing or significan-tly limitin~ the tearing and subsequen-t fracture that otherwise occur at the blade end when the me-tal hook attachment is caught in the workpiece. The reinforcement member of the preferred embodiments has a tapered end or vertex which, because of i-ts shape, displaces the line of high stress and, thus, of severe weakness o~ the blade so that it does no-t coincide with the bending line of the tape as it is flexed. Con-sequently, these lines touch only at the vertex of the reinforcement member. The reinforcement member is separa-te from the metal hook attachment, and accordingly, is not subject to the fatique duty of the metal hook as the hook is applied to the workpiece.
The embodiments illustrated and described are for illustrative purposes only and are not intended -to limit the scope of the invention. Some embodiments may have a tapered end substan-tially circular or ellip-tical.
Accordingly, the term tapered is used generically to include these and other similar shapes.
The terms and expressions which have been employed are used as terms of description and not of limita-tion and there is no intention in the use o:E such terms and expres-sions of excluding any equivalents of the features shown and described or por-tions thereof, but it is recognized that various modifica-tions are possible within the scope of the inven-tion claimed.
INDEX
tape housing 10 blade member 12 finger tab attachment 14 rivets 16 abutting end 18 reinforcement member 20 vertex 22 eyelet 24 adjoining free end 26 concave upper surface 28 supporting end 32 aperture 34 end 36 convex lower surface 38 tapered edges 44 longitudinal slots 46 gap 48 gap 50 inner surface 52 outer surface 54 cuppecL washers 56 spot welds 30 fibreglass tab 58 clear plastic reinforcement member 60 vertex end 61 reinforcement strip member 62 semicircular ends 64 wire mesh reinforcement member 66 epoxy powder coatecL reinforcement member 68 measuring scale 70 13a ~ ~3~i3 INDEX
tape housing 10 blade member 12 finger tab attachment 14 rivets 16 abutting end 18 reinforcement member 20 vertex 22 eyelet 24 adjoining free end 26 concave upper surface 28 supporting end 32 aperture 34 end 36 convex lower surface 38 tapered edges 44 longitudinal slots 46 gap 48 gap 50 inner surface 52 outer surface 54 cupped washers 56 spot welds 30 fibreglass tab 58 clear plastic reinforcement member 60 vertex end 61 reinforcement strip member 62 semicircular ends 64 wire mesh reinforcement member 66 epoxy powder coated reinforcement member 68 measuring scale 70 13a
a metal hook finyer tab attachment and a reinforcement member having a decreasing width in a direction opposite the blade end. The reinforcement member is preferably secured to the blade member by an eyelet adjacent a ver-tex of the reinforcement member. The other end of the reinforce-ment member is secured to the blade member by two rivets and, preferably, has a width smaller than that of said blade member. The reinforcement member is of substantially the same transverse radius of curvature as the blade member and lies adjacent -to and in close uniform contact with the curved surface of the blade member. It is preferably so located that the longitudinal center lines of the blade membex and reinforcement member are substantially coincident.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to describe the present invention more fully the following drawings are provided in which:
Fig. 1 is a perspective view of a retractable tape measure in its housing shown with the blade member and adjoining metal hook finger tab attachment in partially extended position;
Fig. 2 is an enlarged bottom view of the blade member with metal hook attached taken along the line 2-2 of Fig. 1 and showing a preferred form of the reinforcement member;
Fig. 3 is a side elevational view of the blade member with the reinforcement member and metal hook finger tab attachment shown in solid lines in the normal position and the hook member shown in broken lines in a distorted posltlon;
Fig. 4 is an enlarged sectional view of the blade member taken along the line 4-4 of Fig. 3;
31~Si3 Fig. 5 is a further enlarged sectional view of ~he blade member with reinforcement member and metal hook finger tab attachment taken along the line 5~5 of Fig. 2;
Fig. 6 is a bottom view of yet another embodiment showing the reinforcement member secured to the blade member by spot welds;
Fi~. 7 is an enlarged side elevational vi~w of the embodiment of Fig. 6 taken along the line 7-7 of Fig. 6;
Fig. 8 is a bottom view of still another embodi~
ment showing a gently tapering fibreglass tab reinforcement memher adhered to the bottom of the blade;
Fig. 9 is an enlarged side elevational view of the embodiment of Fig. 8 taken along the line 9-9 of Fig. 8;
Fig. 10 is a top view of an embodiment showing a clear plastic reinforcement member adh~red to the face of the blade;
Fig. 11 is an enlarged side elevational view of the embodiment of Fig. 10 taken along the line 11-11 of Fig. 10;
Fig. 12 is a bottom view of an embodiment showing a reinforcement member in the form of a narrow strip disposed some distance away from the blade end extremity;
Fig. 13 is an enlarged side elevational view of the embodiment of Fig. 12 taken along the line 13-13 of Fig. 12;
Fig. 14 is a bottom view of an embodiment showing a reinforcement member in the form of wire mesh or poly~mesh;
Fig. 15 is an enlarged side elevational view of the embodiment of Fig. 14 taken along the lines of 15-15;
3~S3 Fig. 16 is a bottom view of an epo~y p~wder-coated blade member and reinforcement member secured by epoxy adhesive ~o ~he blade memher; ~d Fig. 17 is a side elevational view of the embodi-ment of Fig. 16 taken along the line 17-17 of Fig. 16.
DETAIhED DESCRIPTION OF
TEIE lNv~ ION
~ eferring to Fig. 1, reinforced blade member 12 of the retractable tape measure of this embodiment is ~hown with blade member 12 exposed in sli~htly extPn~e~
position from tape housing 10. slade melDber 12 has metal hook finger tab attachmerlt 14 held by ~wo ri~vets 16 on its c:onc:ave uppex surface 28. Fi~ger tab attachment 14 c:om-prises abutting end 18 and supportin~ end 32.
The supporting end 32 has tapered edges 33. Abutting end 18 normally abuts 'che workpiece when the tape measure is in use and is slidably movable along the longitudinal axis of blade member 12. Abut~ing end 18 is perpendicular to supportiIlg erld 32 which engages ~he blade m~mber 12.
Blade me~b~r 12 is rewound throug~ aperture 34 of tape housing 10 when the tape is not in use.
In Fig. 2 reinforcement member 20 of this pre-ferred embodiment has a varying width which decreases to a narrow end or vertex 22 remote from adjoi~ing free end 26 of blade member 12 and is held by eyelet 24 (or a rivet~
to blade member 12. The other end 36 of reinforcement member 20 is secur~d to convex lower surface 38 of blade member 1~ by two rivets 16 which also secure the supporting end 32 (in dotted lines) of finger tab attachme~t 14 to concave upper surface 28 (Fig. 1). Abutting end 18 of finger tab attac~ment 14 is shown in e~tended position from adjoining free end 26 of blade member 12. Finger ~ab ~3~ii;11 attachment 14 is slidable between the extended position shown in Fig. 2 and a retracted position (not shown) so as to accomnodate both inside and outside measurements.
Reinforcement member 20 is shown with other end 36 of a width smaller than that of adjoining free end 26 of blade member 12 and is located on blade member 12 so that the longitudinal center lines of said blade member 12 and said reinforcement member 20 are substantially concident.
Vertex 22 of of reinforcement member 20 and securing rivets 16 preferably all lie on the longitudinal axis of tape blade member 12.
In Fig. 3 abutting end 18 is shown in solid lines in normal position perpendicular to the longitudinal axis of blade member 12 and in broken lines in dis-torted position such as occurs when the tape measure has been subjected to abuse, e.g., when the finger tab attachment 14 has been caught in the workpiece. Under conditions of such abuse reinforcement member 20 remains relatively in-tact, secured to blade member 12 at its vertex 22 by eyelet 24 (or a rivet) and at other end 36 by rivets 16.
Reinforcement member 20 tapers to vertex 22. As shown in Fig. 3, there is vir-tually no overlap between eyelet 24 and vertex 22 of blade member 12. Because there is negligible overlap at this extremity, the possibility of vertex 22 being caught in the workpiece is i ni i zed.
Tapered edges 44 allow the distribution of the reinforce-ment effect of the reinforcement member 20 to change gradually from a maximum in the region of the rivets 16 of blade member 12 to a minimum at vertex 22, thereby avoiding a sudden loss in reinforcing support. Because -the junction of the supported ancl unsupported parts of blade member 12 ~33~3S:3 define a line of high stress and, therefore, of severe weakness, reinforcement member 20 also avoids a coincidence of the bending line of blade member 12 (as the blade is fle~ed) with that line of weakness.
In Fig. 4 blade member 12 is shown secured between supporting end 32 of finger tab attachment 14 on concave upper surface 28 and reinforcement member 20 on convex lower surface 38. Abutting end 18 is shown perpen-dicular to the longitudinal axes of blade member 12. The location of reinforcement member 20 on convex lower sur-face 38 tends to r~X~rl 7e the reinforcement effect of reinforcement member 20 on blade member 12.
In Fig. 5 eyelet 24 and rivets 16 are shown disposed on a longitudinal axis of blade member 12.
Eyelet 24 supports reinforcement member 20 at vertex 22 thereby providing negligible overlapping of supporting member 20 at eyelet 24. Finger tab attachment 14 is shown with abutting end 18 in e~tended position for outside measuring use of the tape. The gap 48 between abutting end 18 and adjoining free end 26 of blade member 12 corre-sponds to gap 50 in each of longitudinal slots 46 in supporting end 32. Rivets 16 project through longitudinal slots 46 thereby allowing supporting end 32 of finger tab attachment 14 to be longitudinally slidable. During outside measurement inner surface 52 of abutting end 18 abuts the workpiece and abutting end 18 is extended as shown. For inside measurement outer surface 54 abuts the workpiece thereby causing gaps 48 and 50 to close.
Several alternative embodiments of the instant invention are shown in subsequent drawings. The reinforcing effect, of course, will vary for each embodiment shown.
33~3 In Figs. 6-17, parts which are common to the parts shown in Figs. 1-5 are identified by the same nur~er.
In Figs. 6 and 7 reinforcement member 20 is secured to blade member 12 by spot welds 30 adjacen-t the vertex 22 and longitudinal side edges 42. This embodiment offers an alternate form of securing reinforcement member 20 to blade member 12 and, as shown in Fig. 6, increases the number of poin-ts at which supporting member 20 is secured to blade member 12.
In Figs. 8 and 9 a gently tapering fibreglass tab 58 is shown in place of reinforcement member 20 of Fig. 6 and 7. Fibreglass tab 58 is adhered to convex lower surface 38 of blade member 12. Thus, the embodiment of Fig. 8 offers maximum securement of the fibreglass tab 58 strengthening piece to blade member 12.
In Figs. 10 and 11 a clear plastic reinforcement member 60 is shown adhered to concave upper surface 23 of blade member 12 secured thereto by rivets 16 which also secure supporting end 32 of finger tab attachment 14. If desired, at least the vertex end 61 o~ the clear plastic reinforcement member 60 may be adhesively secured to the face (concave upper surface 28) of blade member 12 to facilitate -the rewinding o~ blade member 12 into tape housing 10. Since plastic reinforcement member 60 is transparent, reading of measuring scale 70 on concave upper surface 28 is uni ~:cded.
In Figs. 12 and 13 reinforcement strip member 62 is shown with a cross sectional width substantially smaller than that of the embodiment illustrated in Figs~ 10 and 11.
Reinforcement strip member 62 has substantially semicircular ends 64 which, like the other embodiments discussed above, ~3~
are tapered and thereby avoid having the bending and high stress lines coincide. Reinforcement strip member 62 is shown secured to convex lower surface 38 by an eyelet 24 (or rivet3 at one end and by a rivet 16 at the other end, which rivet also s~cures supporting end 32 of finger tab attachment 14. In the embodiment of Fig. 12 reinforcement strip member 62 is displaced from adjoining free end 26.
In Figs. 14 and 15 an alternative embodiment showing a wire mesh (or polymesh) reinforcement member 66 is the strengthening piece and is secured to convex lower surface 38 of blade member 12 by an appropriate adhesive coating.
In Figs. 16 and 17 an epoxy powder coated rein-forcemènt member 68 is secured to convex lower surface 38 of epoxy powder coated blade member 12 by an epoxy adhesive coating.
Tests were conducted to obtain physical data comparing ~he standard blade with the reinforced blade of this invention. The results, set forth in Table 1 below, show a substantial increase in strength with the reinforced blade -- especially in the high stress angles of pull at 90 degrees upward and 90 degrees downward with reference -to the position of the finger tab.
Six groups of blades were tested, consisting of 1/2", 3/4" and 1" width blades of both standard and rein-forced design. Each blade was clamped in a holding fixture into which a dynamometer was hooked. The finger tab was then clamped in a vise and the whole assembly was pulled manually from varying angles relative -to the vise. An approximate force limitation was observed as a cut-off for safety (1/2" wide reinforced blades showed failures between ~3~3 90 lbs. and 110 lbs. at 90 degrees up and 90 degrees down~. Data wa~ recorded after each pull.
The compiled data in Table 1 (below) indicate a substantial gain in strength by the reinforced blade when compared with the standard design. While the ultimate s-trength of the reinforced blade was not fully determined, the cut-off limit was used as a benchmark with which the standard blade was compared. ThereEore, it should ~e noted that other -testing methods might yield higher gains in strength for the reinforced design.
However, the data indicates the gain for the 1/2" wide reinforced design to be at least 5.1 times greater than the standard blade in the 90 degree upward pull while gaining at least a si~ fold increase in the 90 degree downward pull. Lesser gains in strength show up for the smaller angles of pull for two reasons: the first, that less bending stress is exerted on the blades from finger tabs and rivets; and the second, that the standard blade data is compared with the pull limitation data where breakage did not occur.
The 3/4" wide reinforced blades ~howed larger gains in strength than the 1/2" wide blades. In the 90 degree upward pull, the reinforced design showed at least an eight fold advantage, while the 90 degree downward pull revealed at least a 13.8 times increase over the standard design. The smaller angles showed only one failure for the standard blades (45 degree upward pull at 70 lbs.).
The 1" wide reinforced blade showed similar resul-ts in the test. A strength increase of at least 9.3 times was achieved over the standard results in the 90 degree upward pull. The 90 degree pull showed a 6.5 times advantage by the reinforced design. However, the tests performed with the lesser angles of both -the standard design and the reinforced design resulted in no failures.
Table 1 ABUSE TEST RESULTS DATA SUMMARY
Avera~e Force (Lbs.) Req'd. For Blade Failure Pull 1/2" Wide 1/2" Wide Angle Standard Blades Reinforced Blade 90 Up 21.5 lQg.2 33% failed 90 Down 18.8 112 (no failures) 60 Up 41.9 128.3 "
60 Down 55.0 101.3 50~ failed 45 Up 76.9 62h failed 101. 6 (no failures~
45 Down 93.3 (no failures) 120 "
0 ~No Breakage) 101.6 (Avg.) for 137.5 ~Avg.) or three blades two blades Pull 3/4/" Wide 3/4/" Wide Angle Standard Blade Reinforced Blade 90 Up 12.6 110(no failures) 90 Down 8.2 112.9 "
60 Up 100 (no failures) 110~ "
60 Down No Data 110 I' 45 Up 116.3 (no failures) 120 one failure at 70 45 Down 100 ~no failures) 110 0 (No Breakage) 105.0 (Avg.) for 120.0 two blades Pull 1" Wide 1" Wide Standard Blade Reinforced Blade 9oo Up 10.7 111.3 (no failures) 90 Down 18.3 119.0 60 Up 110.0 (no failures) 107.5 "
60 Down 110.0 " 120/0 "
45 Up No Data 112.5 "
45 Down 110.0 (no failures) 115.0 "
0 (No Breakage) 115.0 110.0 (Avg.) for two blades ~3~
As is illustrated by the drawings and the Abuse Test Results Data Summary of Table l, the improved reinforced blade end for the retractable tape measure of this invention provides increased stren~th and durability at the blade end thereby preventing or significan-tly limitin~ the tearing and subsequen-t fracture that otherwise occur at the blade end when the me-tal hook attachment is caught in the workpiece. The reinforcement member of the preferred embodiments has a tapered end or vertex which, because of i-ts shape, displaces the line of high stress and, thus, of severe weakness o~ the blade so that it does no-t coincide with the bending line of the tape as it is flexed. Con-sequently, these lines touch only at the vertex of the reinforcement member. The reinforcement member is separa-te from the metal hook attachment, and accordingly, is not subject to the fatique duty of the metal hook as the hook is applied to the workpiece.
The embodiments illustrated and described are for illustrative purposes only and are not intended -to limit the scope of the invention. Some embodiments may have a tapered end substan-tially circular or ellip-tical.
Accordingly, the term tapered is used generically to include these and other similar shapes.
The terms and expressions which have been employed are used as terms of description and not of limita-tion and there is no intention in the use o:E such terms and expres-sions of excluding any equivalents of the features shown and described or por-tions thereof, but it is recognized that various modifica-tions are possible within the scope of the inven-tion claimed.
INDEX
tape housing 10 blade member 12 finger tab attachment 14 rivets 16 abutting end 18 reinforcement member 20 vertex 22 eyelet 24 adjoining free end 26 concave upper surface 28 supporting end 32 aperture 34 end 36 convex lower surface 38 tapered edges 44 longitudinal slots 46 gap 48 gap 50 inner surface 52 outer surface 54 cuppecL washers 56 spot welds 30 fibreglass tab 58 clear plastic reinforcement member 60 vertex end 61 reinforcement strip member 62 semicircular ends 64 wire mesh reinforcement member 66 epoxy powder coatecL reinforcement member 68 measuring scale 70 13a ~ ~3~i3 INDEX
tape housing 10 blade member 12 finger tab attachment 14 rivets 16 abutting end 18 reinforcement member 20 vertex 22 eyelet 24 adjoining free end 26 concave upper surface 28 supporting end 32 aperture 34 end 36 convex lower surface 38 tapered edges 44 longitudinal slots 46 gap 48 gap 50 inner surface 52 outer surface 54 cupped washers 56 spot welds 30 fibreglass tab 58 clear plastic reinforcement member 60 vertex end 61 reinforcement strip member 62 semicircular ends 64 wire mesh reinforcement member 66 epoxy powder coated reinforcement member 68 measuring scale 70 13a
Claims (14)
1. A retractable tape measure comprising:
a housing;
a blade member;
a finger tab attachment having a tapered section secured to an end of said blade member; and a reinforcement member having a varying width which decreases to a narrow end remote from an adjoining free end of said blade member, said rein-forcement member being centered about the longitudinal axis of the blade, and said reinforcement member being secured to said blade member by a first securing means comprised of an eyelet adjacent said narrow end and by a second securing means comprised of two rivets which lie along the longitudinal axis of said blade member and wherein said second securing means is less remote than the first securing means from said free end of said blade member.
a housing;
a blade member;
a finger tab attachment having a tapered section secured to an end of said blade member; and a reinforcement member having a varying width which decreases to a narrow end remote from an adjoining free end of said blade member, said rein-forcement member being centered about the longitudinal axis of the blade, and said reinforcement member being secured to said blade member by a first securing means comprised of an eyelet adjacent said narrow end and by a second securing means comprised of two rivets which lie along the longitudinal axis of said blade member and wherein said second securing means is less remote than the first securing means from said free end of said blade member.
2. A retractable tape measure as described in claim 1 wherein the reinforcement member has a concave upper surface abutting a convex lower surface of said blade member.
3. A retractable tape measure as described in claim 2 wherein the finger tab attachment is slidably mounted on a concave upper surface of the blade member and is secured thereto by said rivets.
4. A retractable tape measure as described in claim 3 wherein the finger tab attachment has an abutting end which abuts a workpiece and is slidably movable along the longitudinal axis of the blade member when the workpiece is contacted by the abutting surface.
5. A retractable tape measure as described in claim 1 wherein the reinforcement member comprises a fibreglass tab and wherein said first securing means comprises an adhesive.
6. A retractable tape measure as described in claim 1 wherein the reinforcement member comprises a strip member displaced from an adjoining blade edge of said blade member and having substantially semicircular ends secured by a rivet at each end.
7. A retractable tape measure comprising-a transversely curved blade member having concave-convex surfaces;
a finger tab attachment having a tapered section secured to an end of said blade member; and a tapered reinforcement member being centered about the longitudinal axis of the blade, said reinforcement member having one end secured to the blade member by a first securing means comprised of an eyelet adjacent a vertex of the reinforcement member, the other end of said reinforcement member being secured to the blade member by a second securing means comprised of two rivets which lie along the longitudinal axis of said blade member and having a width smaller than that of said blade member, said reinforcement member being of sub-stantially the same transverse radius of curvature as said blade member and lying adjacent to and in substantially close uniform contact with said blade member and being located so that the longitudinal center lines of said blade member and said rein forcement member are substantially coincident.
a finger tab attachment having a tapered section secured to an end of said blade member; and a tapered reinforcement member being centered about the longitudinal axis of the blade, said reinforcement member having one end secured to the blade member by a first securing means comprised of an eyelet adjacent a vertex of the reinforcement member, the other end of said reinforcement member being secured to the blade member by a second securing means comprised of two rivets which lie along the longitudinal axis of said blade member and having a width smaller than that of said blade member, said reinforcement member being of sub-stantially the same transverse radius of curvature as said blade member and lying adjacent to and in substantially close uniform contact with said blade member and being located so that the longitudinal center lines of said blade member and said rein forcement member are substantially coincident.
8. A retractable tape measure as described in claim 7 wherein said first securing means is a spot weld.
9. A retractable tape measure as described in claim 8 wherein said reinforcement member is further secured to the blade member by spot welds located adjacent the longitudinal side edges of said reinforcement member.
10. A retractable tape measure as described in claim 7 wherein said reinforcement member comprises clear plastic and is secured to said blade member on a surface bearing the measuring scale of said blade member.
11. A retractable tape measure as described in claim 7 wherein said reinforcement member comprises wire mesh and said first securing means comprises an adhesive.
12. A retractable tape measure as described in claim 11 wherein said reinforcement member is further secured to the blade member by an adhesive coating.
13. A retractable tape measure as described in claim 7 wherein said reinforcement member and said blade member are coated with epoxy powder and said first securing means comprises an epoxy adhesive.
14. A retractable tape measure as described in claim 13 wherein said reinforcement member is further secured to the blade member by an epoxy adhesive coating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000417225A CA1193853A (en) | 1982-12-08 | 1982-12-08 | Reinforced blade end for a retractable tape measure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000417225A CA1193853A (en) | 1982-12-08 | 1982-12-08 | Reinforced blade end for a retractable tape measure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1193853A true CA1193853A (en) | 1985-09-24 |
Family
ID=4124095
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000417225A Expired CA1193853A (en) | 1982-12-08 | 1982-12-08 | Reinforced blade end for a retractable tape measure |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1193853A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4930227A (en) * | 1989-02-21 | 1990-06-05 | The Stanley Works | Coilable tape rule with improved end hook |
| US5010657A (en) * | 1989-06-29 | 1991-04-30 | Cooper Industries, Inc. | Tape measure end hook |
-
1982
- 1982-12-08 CA CA000417225A patent/CA1193853A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4930227A (en) * | 1989-02-21 | 1990-06-05 | The Stanley Works | Coilable tape rule with improved end hook |
| US5010657A (en) * | 1989-06-29 | 1991-04-30 | Cooper Industries, Inc. | Tape measure end hook |
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